In lighting devices using a light emitting device, a heat sink, dissipating heat from a light emitting device is generally disposed to the rear of a board on which the light emitting device is mounted. However, in order to avoid degradations in performance of lighting devices caused by insufficient heat dissipation efficiency, various measures have been adopted to enhance the heat dissipation efficiency of lighting devices.
Also, lighting devices using a light emitting device employ light emitting diodes (LEDs) having strong directivity as light sources, and thus, light may only be distributed in limited directions. Meanwhile, incandescent lamps are available to substantially distribute light in all directions, excluding a region covered by a metal socket thereof, or the like. Thus, in a case in which light needs to be substantially distributed in all directions, LED lighting devices may not be appropriate as substitutes for incandescent lamps. Thus, a technique of enhancing light distribution is required in the field of LED illumination devices.